Adjustable scaffold-trestle.



G. W. JOHNSON.

ADJUSTABLE SGAFFOLD TRESTLE.

APPLICATION FILED 00114, 1911.

Patented June 10, 1913.

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UNITED STATES PATENT QFFIQE.

GEORGE W. JOHNSON, OF ATLANTIC, IOWA.

ADJUSTABLE SCAFFOLD-TRESTLE.

T 0 all whom it may concern:

Be it known that I, GEORGE IV. JOHNSON, a citizen of the United States, residing at Atlantic, in county of Cass and State of Iowa, have invented certain new and useful Improvements in Adjustable Scaffold- T restles, of which the following is a specification.

My invention relates to an improvement in adjustable scaffold trestles, and the object is to provide a trestle which is so constructed that it will hold a single board or a stringer upon which a platform may be built at any height from the floor.

A further object is to provide a device of the character described which may be used upon an uneven surface, and which is equally adjustable as to height and angle.

The invention consists of certain novel features of construction and combinations of parts which will be hereinafter fully described and pointed out in the claim.

In the accompanying drawings, Figure 1 is a view in perspective of the invention; and Fig. 2 is a horizontal section through the upper part of the device.

The frame A is composed of base bars 1, 1, connected together by the connecting bar 2. Uprights 3, 3, are secured to the base bars at their lower ends, and have the upper ends thereof connected by a rigid supporting bar 4. Braces 5, 5, are secured to the supporting bar 4, and the base bars 1. The cross bar 6 is suspended beneath the supporting bar by chains 7, 7, which pass through the openings 8, 8, in the wear plates 9, 9, secured to the cross bar, and these chains are held in their adjusted position by inserting pins 10, 10, through one of the links thereof. The cross bar is held so that it will slide in the same plane as the uprights 8 by means of plates 11, 11, secured to the sides of the cross bar and engaging the sides of the upright.

In the use of the device, to support a single board, the board would be placed directly upon the cross bar 6, and would be held adjustably thereon, but if it is desired to use a stringer upon which a plat-form may be built, uprights 12, 12, are connected to the cross bar, and stringer 13 is held in an upright position therebetween. In some instances it might be desirable to suspend a Specification of Letters Patent.

Application filed October 14, 1911.

Patented June 10, 1913.

Serial No. 554,740.

scaffold above the supporting bar 4, and for this purpose I have provided two sets of upright rods 14, 14, and 15, 15. These rods are secured at the lower end. in the cross bar 6 and pass loosely through the supporting bar and through the wear plates 9. The rods 15, 15, are mounted comparatively close together, and are provided at their upper extremity with a stirrup 16, in which the stringer 13 would be held. The rods 14, 14, are secured at points farther distant from the center which may be even beyond the chains 7, and have a cross head 17 upon the upper end, upon which a single board may be placed or a scaffold built as the occasion may require. In some instances it might be desirable to place a scale 18 along the inner edges of the upright in such a manner that the trestle could be readily adjusted to the exact height required.

It will thus be seen that I have provided a trestle which is simple in construction and operation, and one which is capable of unlimited vertical adjustment. It will also be seen that when the main structure is used without the upwardly projecting rods, the cross bar may be adjusted at an angle to the surface upon which the trestle is placed and thus take up any inequalities which may occur in the surface.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is

In a device of the class described, upright end members, braces therefor, a rigid top bar, a movable bar slidably mounted on said end members, rods fixed to said last named bar and slidably extended through said rigid top bar, a cross plate secured to said rods, above the top bar, means for securing said movable bar in any position of its movement, a pair of parallel upright rods secured to said movable bar and extending through said fixed bar and designed to guide and support the former and to hold a board resting on its edge on said movable bar.

In testimony whereof I affix my signature, in the presence of two witnesses.

GEORGE W. JOHNSON.

lVitnesses RAYMOND P. DUNGAN, PAUL C. OTTO.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

